What is black hole ventilation?

Black hole ventilation is a cheap and easy way to ensure you are keeping your home healthy and discouraging damp from forming in your walls. In this blog we are going to look at exactly what it is, how it works, and why it makes sense to install over traditional and alternative ventilation systems.

What is black hole ventilation?

Black hole vents stop draughts from going through into your home but still allow air to circulate, ensuring a steady supply of fresh air.

With standard ventilators, when outside wind pressure increases, the ventilator lets more air through and creates draughts. Over the years, they have become increasingly restrictive in an attempt to avoid this and also the problem of vermin and insects getting through. Normal grills are often illegal because they are so restrictive they have very little surface area to allow air through. Black holes, on the other hand, combat these two problems.

Inside a ‘black hole’ ventilator, vortices are formed behind the internal blades as the incoming air is forced to change direction. This creates a narrowed gap for the air to pass through. As wind pressure increases, the air flow is restricted, avoiding annoying draughts. The same mechanism prevents insects and vermin getting through the hole, and also blocks light. Moist air therefore diffuses through the vent rather than being blown through!

Why is ventilation important?

Ventilation is important for a number of reasons:

  1. To discourage damp and mould, especially in kitchens and bathrooms, where steam often circulates and settles on walls as condensation.
  2. If you have an open fire, you could be at risk of a dangerous buildup of carbon monoxide.
  3. Avoiding indoor air pollution. This is a bigger problem than many people realise, and can have direct effects on health.

If you have window vents, which are recommended these days, that might be enough. But if you don’t want to replace existing windows, or vents would look out of place on your period property, a discreet black hole vent might be a good alternative.

From our perspective, we see so many properties with mould and damp issues, all down to lack of ventilation, that this really is a no brainer. The amount of blocked vents, either on purpose or through poor maintenance, in older pre war properties is staggering, and the best and cheapest way to deal with this is adding quality ventilation.

How much does it cost to install a black hole vent?

Cost to supply and fit is £70-100 per vent. This will depend somewhat on the type of wall that needs to be cut through and where it needs to be fitted.
If you are having external wall insulation installed, it usually makes sense to get these fitted at the same time. Many properties will have standard traditional vents which will be extended as part of the job, but why not spend that little bit extra and get these modern vents installed at the same time?

If you are concerned about how the vents will look, don’t worry – they come in many different colours shapes and sizes, and will not look very different to your traditional ‘hole in the wall’ vents. You will be amazed at how ventilation reduces your damp problem and creates a more pleasant atmosphere in your home.

Where should you position your vent?

This is not always an easily answered question. There will be aesthetic and practical considerations which means the vent can’t always go where you want it. Your builder should be able to suggest a good location, but the best position is likely to be at height, somewhere near the windows on an external wall. The amount of vents you need will really depend on the scale of the problem and the size of the vent you are installing. In some properties with big damp problems, you might need a couple of vents to deal with the problem. The good news is that it is pretty cheap and easy to come back and install another if the first vent isn’t sufficient.